The present invention relates to control systems and pertains particularly to combined safety and creeper control systems for industrial vehicles.
Many industrial trucks, such as lift trucks and the like, are powered by gasoline engines and include a hydrostatic transmission for transmitting power from the engine of the vehicle to the driving wheels thereof. The hydrostatic transmission employs a hysrostatic motor and pump, and is controlled by varying the displacement of one or the other, or both of the motor and pump to achieve forward and reverse of the vehicle and to control the speed thereof.
Because of the limit on the number of manual control members that an operator can successfully manipulate for control of the vehicle, many functions of the vehicle are combined to single manual control members. For example, the drive and transmission control are normally combined in a single element. While the control system is normally such that the transmission automatically goes to neutral when the throttle control is released to permit the engine to idle, this may not always be the case. For this reason, it is desirable to insure that the transmission is disabled when the vehicle operator leaves the vehicle. Failure to do so may result in the vehicle moving under its own power without the operator present. For this reason it is desirable to have automatic disabling means which automatically disable the vehicle when the operator leaves the seat of the vehicle.